//su dung cau truc if de neu nguoi dung nhap vao so 1 thi hien thi trinh do la beginner 2= intermediate, 3= advanced, 4=profestional,# = khong hop le.
#include<stdio.h>
#include<conio.h>
main(){
       int i;  
       printf("************************************\n");
       printf("* Vui long chon trinh do cua minh: *\n************************************\n   1. Beginner\n   2. Intermediate\n   3. Advanced\n   4. Profestional\n");
       do{
       printf("Nhap vao cac so tuong ung:");
       scanf("%d",&i);
       if(i==1)
       printf("beginner");
       else if(i==2)
       printf("intermediate\n");
       else if(i==3)
       printf("advanced\n");
       else if(i==4)
       printf("profestional\n");
       else
       printf("khong hop le vui long nhap lai\n");
       }
       while((i>=4||i<1));
       getch();
       }
